RIZIN has started filling out its December 31 lineup in Nagoya, and the headline attraction is a featherweight title fight. Unbeaten Razhabali Shaydullaev, who carries a 20-0 record, is set to defend against Kyoma Akimoto, who sits at 13-1, in a bout that's now official for Super RIZIN 6.

Also added to the card is a matchup between Chihiro Suzuki and YA-MAN, which will be contested under MMA rules across three five-minute rounds, according to MiddleEasy.

The biggest storyline outside the title fight might be Seika Izawa's return. RIZIN has confirmed the former women's super atomweight champion for the December 31 show, marking her comeback after giving birth in September. Her opponent has not been announced yet.

Izawa's addition to the card was made official at a press conference held in Nagoya City, Aichi Prefecture, on a holiday Tuesday, per MMAPLANET. At that event, Saori Oshima addressed the possibility of running things back with Izawa down the line, saying, "I think there will definitely be a second (time)."

Putting a former champion back in the mix so soon after childbirth is notable on its own, and doing it without a named opponent yet suggests RIZIN still has matchmaking to finish before the show. Combined with the Shaydullaev-Akimoto title fight and the Suzuki-YA-MAN booking, Super RIZIN 6 is shaping up as one of the promotion's more loaded year-end cards.

With the event still weeks away, expect RIZIN to round out the rest of the New Year's Eve lineup, including whoever steps in across from Izawa, in the coming weeks.